Support 2019

The Antarctic ice sheet represents the largest ice mass on Earth holding about 60% of all fresh water, which is equivalent to ca. 58 m of sea-level rise. As such, the sensitivity of the Antarctic ice sheet to climate change has important implications for the global sea level. Understanding the response of the ice masses to climate fluctuations requires the reconstruction of ice volume changes in the past. In this context, a project is currently conducted aiming to reconstruct the evolution of the East Antarctic Ice Sheet (EAIS) since the Late Miocene (coordinated by N. Akçar, Uni Bern).

To decipher the timing, magnitude and frequency of ice surface lowering and past changes in the drainage pattern of the EAIS, samples from the western Sør Rondane Mountains have been analysed for their cosmogenic 10Be, 26Al, and 36Cl concentrations. However, because the Antarctic ice sheet is characterized by non-erosive cold-based ice, these long-lived nuclides can accumulate over several episodes of surface exposure, which masks the most recent changes in glacier ice volume. This problem can only be solved by analysis of a nuclide of much shorter half-life as given by in-situ cosmogenic 14C. Because of its fast radioactive decay, in-situ 14C is largely removed when shielded from cosmic rays during coverage by glacier ice for ca. 25 kyr, thereby resetting the ‘nuclide clock’ to zero.

Thanks to the travel support by CH-Quat, I was able to visit the Laboratory of Ion Beam Physics at ETH Zürich, where one of the few worldwide existing in-situ 14C extraction systems is hosted. During this visit, a number of selected samples from the western Sør Rondane Mountains could be analysed for their in-situ 14C concentration. Results from these analyses will help gaining a deeper understanding on ice sheet fluctuations in concert with Late Quaternary climate evolution.

During the Last Glacial Maximum (LGM), a local ice-cap covered the Jura Mountains. Outlet glaciers advanced all the way down to the lowlands, and reached amongst others the Ain valley (F). Glaciers blocked the Ain river and caused the building of an ice-dammed lake in the valley. As the glacial geomorphic features and deposits have not been subjected to building, construction and/or production activities, they are well-preserved. LGM advance and deglaciation of the glaciers are geomorphologically well documented. However, their chronology is only reconstructed indirectly. The aim of my master thesis is to reconstruct the chronology of the glacio-lacustrine deposits and to explore the Late Pleistocene deposits and related geomorphological features in detail.

The support of CH-QUAT allowed me to do fieldwork in the Ain valley. In this time, I did sedimentological analysis in one gravel pit, including grainsize distribution, clast petrography, clast morphometry and clast fabric. In addition to that I was able to map the most important geomorphological features in the valley. In a second trip we collected samples for the depth-profile dating with terrestrial cosmogenic nuclides. I am very grateful for the financial support of CH-QUAT.

Contact:
Claudia Burkhalter
claudia.burkhalter(at)students.unibe.ch

C. Burkhalter (Image: N. Akçar)

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C. Burkhalter (Image: N. Akçar)

Ewelina Bros / Labor für Ionenstrahlphysik / ETH Zürich, Switzerland

Attendance to the 20th INQUA Congress in Dublin, Ireland

The CH-QUAT support made it possible for me to attend the 20th Congress of the International Union for Quaternary Research (INQUA) which took place between July 25th to 31st 2019 in Dublin, Ireland. There, I presented my work in a poster entitled “Younger Dryas moraines and relict rockglaciers system in the High Tatra Mountains”, co-authored by Jerzy Zasadni, Piotr Kłapyta, Andrzej Świąder, Lenka Balážovičová, Marcus Christl and Susan Ivy-Ochs. The poster was included in the session “Glaciers, moraines and climate: Challenges of identifying, dating and extracting palaeoclimatic data from former glacier fluctuations”.

This contribution gives a summary of my doctoral project which was focused on the latest glaciations of highest parts of the Carpathians, the High Tatra Mountains as well as the temporal and spatial dimensions of their deglaciation. The project attempts to fill up the gap in the knowledge of the most recent glaciations in the High Tatra Mountains by investigating the chronology and extent of the youngest glaciers which were present in the mountains during the Younger Dryas (YD) cooling. Geomorphological mapping and surface exposure dating using 10Be isotope were used for realising the project goals. Moreover, an attempt of reconstructing the palaeoclimatic conditions during the YD was made. The results contribute to a better understanding of the deglaciation of these mountains at the end of the Pleistocene as well as their climatic conditions at that time. Taking part in the INQUA congress was a great experience combining professional and personal interest. The support of CH-QUAT enabled me as well to take part in one of the mid-congress excursions, which was a wonderful guided tour into a World Heritage Site Brú na Bóinne and Hill of Tara. These sites represent one of the world's most precious prehistoric landscapes including archaeological sites, passage graves and monuments.

I would like to thank the CH-QUAT for supporting my attendance to the INQUA, which provided me with many opportunities to exchange the knowledge with the international scientific community and receive precious feedback from experts in the field. Thank you!

Every four year, the International Union for Quaternary Research (INQUA) organizes an international conference on Quaternary sciences. This time, the congress was held in Dublin from 25th to 31st of July and more than 2000 researchers participated. There were 139 sessions in various disciplines of the Quaternary sciences, e.g. paleoclimatology, terrestrial processes, or stratigraphy and chronology, in this year’s programme. I would like to thank CH-QUAT for supporting my participation at the INQUA congress. I got new insights which are relevant for my research during this conference. For example, the poster presentations as well as the social events were a good opportunity to establish new contacts and to broaden my existing scientific network into an international level.
At this conference, I presented my PhD-project with a poster in the session “River terraces as archives of Quaternary landscape development”. In my PhD project, I investigate the Quaternary sediments in the Swiss Northern Alpine Foreland with the focus on the Deckenschotter deposits, which represent the oldest Quaternary sediments. These deposits at selected sites are studied in detail and their chronology is reconstructed with isochron-burial dating. I presented first results of field sedimentology. I discussed my interpretations with those who visited my poster. Cosmogenic nuclides such as 10Be and 26Al are widely used to calibrate the time in Quaternary geology, however, isochron-burial dating is a rather new method in this field and has been used for about 10 years. I exchanged ideas about this method with several participants. Some were familiar with the various cosmogenic nuclide dating techniques but didn’t know about the isochron-burial dating method. They were interested to know how this method works, to which type of deposits this method can be applied, which requirements have to be fulfilled and which time interval can be dated. Others had already experience with the isochron-burial dating method. With those, I discussed about the advantages, challenges, and limitations the isochron-burial dating technique.

In the area north of Lake Garda, in the region of Nago - Torbole (Trentino, Italy), several landslides dating back to the period after the last glaciation are present. In Trentino, a key issue in assessing hazards from rock wall collapse is determining precisely when the large rock avalanches occurred. In the past up to 8 different landslide bodies have been identified in the area, but there is a possibility that these are correlated to the same event and that the slides not happened in different phases. The goal of this MSc project is to use detailed geomorphological field mapping, remote imagery-supported landform interpretation, cosmogenic nuclide surface exposure dating, and runout modelling to reconstruct failure and emplacement of the Gorte, Navesele and Salto della Capra rock avalanches, in an area strongly damaged by Late Alpine tectonics. In addition, a recent bathymetry survey of the lake Garda will be used.

Thanks to the contribution of the CH-QUAT association, I was able to carry out a total of two weeks of fieldwork this summer and in the autumn, covering part of the costs of travel and accommodation. During these weeks I had the opportunity to make a geomorphological map of the two landslides, as well as to understand the various lithologies involved in the landslides and collect different samples. During winter 2019/2020 the samples will be dated through cosmogenic radionuclides at the laboratories of the ETHZ and the different types of limestone defined through thin sections under the microscope, in collaboration with the University of Padua.

The CH-QUAT funding supported my attendance at the 20th Congress of the International Union for Quaternary Research (INQUA) in Dublin, Ireland. Here I presented the results from my doctoral project in a talk titled “Tracing environmental changes in the islands of Espiritu Santo, Vanuatu” in the session “Late Quaternary environmental changes in the South Pacific: climate, ecosystem dynamics, and human colonization”.

Small islands are paradigmatic cases of anthropogenic impacts on ecosystems. Using lake sediment cores to reconstruct past human activities can help retrieve information about the environmental responses to different rates and degrees of change in these vulnerable ecosystems. On islands in Remote Oceania, the origin and timing of the first human settlements, and consequent ecosystem modifications are still under debate. Past landscape changes have been demonstrated by archaeological, palaeontological, palynological and geomorphological investigations. However, few sedimentological studies have been conducted so far on this topic in the area. In our study, we used a multiproxy approach, combining geochemical tools based on biomarkers (fossil molecules of known origin) with traditional sedimentological methods (total organic carbon, biogenic silica, grain size) on cores from three lakes of the west coast of Espiritu Santo, Vanuatu, each dating back ~ 1000 years. At the INQUA I had the chance to present the project results at one of the most important international scientific events in the field. Here I had the unique opportunity to receive precious feedbacks and to get in contact with experts in the subject. Thank you CH-QUAT!

I am very grateful for the financial support of CH-QUAT my participation in the INQUA 2019 in Dublin, Ireland. Participating this congress gave me good chance to enhance my scientific networking competence and, to join multiple scientific sessions. I am a postdoctoral researcher in the Institute of Geological Sciences at the University of Bern, Switzerland.
I presented “Timing of Quaternary glaciations in eastern Turkey, inferred from 36Cl cosmogenic dating” as a poster in INQUA 2019. In this study, I investigated Late Quaternary glaciations in the mountains of eastern Turkey. Because Turkey is located in the Alpine-Himalayan mountain belt, it has a mountainous landscape with ranges extending parallel to the coast in the north and south. This landscape causes moist air masses to leave precipitation mostly in the coastal regions. Therefore, the central parts of Turkey have lower precipitation compared to the coast, and the continental climate prevails. This inbalance results in different equilibrium line altitudes (ELA) on the coast and inland. In order to explore, in this study, how this inbalance in the past was and how it was changing in time and space, we focus on the remnants of past glaciations in the eastern Turkish mountains, where significant evidence of past glaciations are present, but poorly constrained. To do so, we studied the glacial geology in the Kavuşşahap Mountains, Mount Bingöl, Munzur Mountains and Tahtalı Mountains in detail and reconstructed the glacial chronology with surface exposure dating.

The travel support from CH-QUAT allows me to participate on additional fieldwork to collect Late-Quaternary swamp and lake sediment cores with a multidisciplinary team from study sites located in northern Tanzania. The coring sites are located alongside archaeological work across the Greater Serengeti Ecosystem that includes Lake Victoria, semi-arid savannahs, and montane forests. The aim is to generate datasets of vegetation and erosion histories derived from pollen, charcoal, and sedimentologic analyses and combine these data with evidence of human land use from archaeology. Together with additional evidence of land use and land cover change derived from archival sources and air photographs, a long-term description of vegetation change will be useful for analysing human-environment interactions across the region.

During fieldwork in 2018 a gravity core was collected from small boats on Speke’s Gulf (Lake Victoria) and has encouraging lead-210 dated results and initial pollen processing shows that it should provide a record of savannah vegetation change in the region over the past 200 years. During this time, several major changes occurred in the region due to the decimation of herbivore megafauna, the establishment of Colonial farming settlements, mining activities, deforestation, and the introduction of Nile Perch to the lake. An exploratory palustrine sediment core was also collected from inside Serengeti National Park. During upcoming fieldwork in summer 2019, we will return to collect deeper sediments from the lake inside the park and collect lake sediments from the lakes in montane forests of Ngorongoro Crater.

I am grateful for the support from CH-QUAT that propels my continued engagement to study tropical palaeoenvironments within this multidisciplinary project.